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DESCRIBE QUERY

  • Článek

Platí pro:zaškrtnutí označeného ano Databricks SQL zaškrtnutí označeného ano Databricks Runtime

Vrátí metadata výstupu dotazu.

Syntaxe

{ DESC | DESCRIBE } [ QUERY ] input_statement

Parameters

  • DOTAZ

    Tato klauzule je nepovinná a může být vynechána.

  • query

    Dotaz, který se má popsat.

Příklady

-- Create table `person`
> CREATE TABLE person (name STRING , age INT COMMENT 'Age column', address STRING);

-- Returns column metadata information for a simple select query
> DESCRIBE QUERY SELECT age, sum(age) FROM person GROUP BY age;
 col_name data_type    comment
 -------- --------- ----------
      age       int Age column
 sum(age)    bigint       null

-- Returns column metadata information for common table expression (`CTE`).
> DESCRIBE QUERY WITH all_names_cte
    AS (SELECT name FROM person) SELECT * FROM all_names_cte;
 col_name data_type comment
 -------- --------- -------
     name    string    null

-- Returns column metadata information for an inline table.
> DESCRIBE QUERY VALUES(100, 'John', 10000.20D) AS employee(id, name, salary);
 col_name data_type comment
 -------- --------- -------
       id       int    null
     name    string    null
   salary    double    null

-- Returns column metadata information for `TABLE` statement.
> DESCRIBE QUERY TABLE person;
 col_name data_type    comment
 -------- --------- ----------
     name    string       null
      age       int  Agecolumn
  address    string       null